Re: secure comparision protocol



"roy" <royliuk@xxxxxxxxxxx> wrote in message
news:1140144585.746546.38030@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Far from perfectly secure, and open to lies but, having everyone answer
increasingly precise questions about there numbers e.g. Is your number
greater than 12? you can filter them, and if you refrain from asking to
final precision there is the potential for some error in the knowledge. This
should work if you have sparse enough numbers, but if you get to the point
where the maximum number is between 22 and 24 you've clearly revealed the
number.

The second part, it is possible through collusion and lying under the
protocol I gave, but I can't think of an honest protocol without a trusted
third party involved to do this.
Joe


.